Nakamoto Masahiko, Hirayama Hiroaki, Sato Yoshinobu, Konishi Kozo, Kakeji Yoshihiro, Hashizume Makoto, Tamura Shinichi
Division of Image Analysis, Osaka University Graduate School of Medicine, Japan.
Med Image Anal. 2007 Oct;11(5):429-42. doi: 10.1016/j.media.2007.07.009. Epub 2007 Aug 19.
The present paper describes a method for intraoperative recovery of respiratory motion and deformation of the liver by using a laparoscopic freehand 3D ultrasound (US) system. The proposed method can extend 3D US data of the liver to 4D by acquiring additional several sequences of time-varying 2D US images during a couple of respiration cycles. 2D US images are acquired on several sagittal image planes and their time-varying 3D positions and orientations are measured using a miniature magnetic 3D position sensor attached to a laparoscopic US (LUS) probe. During the acquisition, the LUS probe is assumed to move together with hepatic surface. Respiratory phases and in-plane 2D deformation fields are estimated from time-varying 2D US images, and then time-varying 3D deformation fields on sagittal image planes are obtained by combining 3D positions and orientations of the image planes. Time-varying 3D deformation field of the volume, that is, 4D deformation field, is obtained by interpolating the 3D deformation fields estimated on several planes. In vivo experiments using a pig liver showed that the proposed method could perform accurate estimation of respiratory cycle and in-plane 2D deformation fields. Furthermore, evaluation for the effects of sagittal plane interval indicated that 4D deformation fields could be stably recovered.
本文介绍了一种利用腹腔镜徒手三维超声（US）系统在术中恢复肝脏呼吸运动和变形的方法。所提出的方法通过在几个呼吸周期内采集额外的几序列随时间变化的二维超声图像，可将肝脏的三维超声数据扩展为四维数据。在几个矢状图像平面上采集二维超声图像，并使用连接到腹腔镜超声（LUS）探头的微型磁性三维位置传感器测量其随时间变化的三维位置和方向。在采集过程中，假设LUS探头与肝表面一起移动。从随时间变化的二维超声图像估计呼吸相位和面内二维变形场，然后通过组合图像平面的三维位置和方向获得矢状图像平面上随时间变化的三维变形场。通过对在几个平面上估计的三维变形场进行插值，获得体积的随时间变化的三维变形场，即四维变形场。使用猪肝进行的体内实验表明，所提出的方法能够准确估计呼吸周期和面内二维变形场。此外，对矢状面间隔影响的评估表明，可以稳定地恢复四维变形场。
